1. Field of the Invention
The present invention generally relates to a micro fluxgate sensor. More particularly, the present invention relates to a micro fluxgate sensor manufactured by a micro-machining technique using an amorphous magnetic core and a method of manufacturing the same.
2. Description of the Related Art
A fluxgate sensor is a device that detects magnetic energy, which is not perceivable by human sense organs. Such a magnetic detection sensor may be used in applications that require detection of a magnetic energy formed around a circumference. For example, these applications may include position identification of airplanes, vessels and vehicles, motion detection in a virtual reality space, geomagnetic compensation and dot noise compensation for high definition television (HDTV), magneto-encephalograph (MEG) measurement acquisition in a medical device, and others. Recently, since the fields of application have gradually spread, there has been a trend toward providing devices that are thinner, lighter and less expensive. Correspondingly, there has been an attempt to provide a fluxgate sensor that is thinner, lighter and less expensive.
A micro fluxgate sensor primarily includes a core made of soft magnetic material, an excitation coil wound around the core for inducing a magnetic field when a current is applied thereto, and a magnetic field detecting coil for detecting an effect of an external magnetic field on the magnetic field induced by the excitation coil. A basic detecting principle utilizes a nonlinear characteristic of the soft magnetic core, i.e., a saturation characteristic. If a proper alternating current (AC) is applied to the excitation coil to induce the magnetic field, a flux density in the core is periodically saturated. At that time, if the external magnetic field to be measured is applied, the flux density of the core varies. The magnetic field detecting coil measures a variation of the flux to determine a dimension, either strength or direction, of the external magnetic field.
In order to manufacture a micro fluxgate sensor, a coil is generally wound around a large, bar-type core or a ring-type core of a soft magnetic ribbon. Accordingly, the core itself becomes relatively large, thereby enlarging a volume of the core and increasing a manufacturing cost of the core. In addition, since the flux variation generated by the excitation coil and the detected magnetic field do not prevent a flux leakage due to the core, highly sensitive detection of the magnetic field is not readily achieved.
Recently, a method utilizing a layering technique of a printed circuit board has been developed to manufacture a thinner and lighter fluxgate sensor.
According to the method utilizing the layering technique of the printed circuit board, an insulating layer and a copper plate are bonded to either side of a soft magnetic core, thereby producing an excitation coil and a magnetic field detecting coil, each wound around the core. In this method, since the core must be drilled to wind the coil around the core, the device may be damaged during the drilling process. Regarding another disadvantage, it is more difficult to downsize a fluxgate sensor manufactured according to this method as compared to one produced by a micro-machining technique.